A US spacecraft has captured images of Apollo landing sites on the Moon, revealing hardware and a trail of footprints left on the lunar surface.

一架美国宇宙飞船获得了阿波罗的月球着陆影象，显示月球表面留有飞船硬件和脚印。

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Science instruments (circled left) and the lunar module lower stage (circled right) are connected by a footprint trail

The release of the images coincides with the 40th anniversary of the first manned mission to land on the Moon.

The descent（降落，侵袭） stages from the lunar modules²（模块） which carried astronauts to and from the Moon can clearly be seen.

The image of the Apollo 14 landing site shows scientific instruments and an astronaut footpath³ in the lunar dust.

It is the first time hardware left on the Moon by the Apollo missions has been seen from lunar orbit.

The pictures were taken by Nasa's Lunar Reconnaissance Orbiter (LRO) spacecraft, which launched on 18 June.

The spacecraft is carrying three cameras on board: one low-resolution wide-angle camera and two high-resolution narrow-angle cameras mounted side-by-side.

These are known collectively as the Lunar Reconnaissance Orbiter Camera (LROC) instrument.

"The LROC team anxiously awaited each image," said the instrument's principal investigator⁴ Mark Robinson of Arizona State University.

"We were very interested in getting our first peek⁵ at the lunar module descent stages just for the thrill - and to see how well the cameras had come into focus. Indeed, the images are fantastic and so is the focus."

Astronaut trail

The camera instrument was able to capture five of the six Apollo sites, with the remaining Apollo 12 site expected to be photographed in the coming weeks.

Future LROC images from these sites will have two to three times greater resolution.

Long shadows from a low sun angle make the locations of the lunar modules' descent stages particularly evident.

The image of the Apollo 14 landing site had a particularly desirable lighting⁶ condition that revealed additional details.

The Apollo Lunar Surface Experiment Package, a set of scientific instruments placed by the astronauts at the landing site, is discernable（可辨别的）, as are the faint trails between the module and instrument package left by the astronauts' footprints.

The LRO satellite reached lunar orbit on June 23 and captured the Apollo sites between July 11 and 15.

Though it had been expected that LRO would be able to resolve the remnants（残余） of the Apollo mission, these first images were taken before the spacecraft reached its final mapping orbit.

"Not only do these images reveal the great accomplishments⁷ of Apollo, they also show us that lunar exploration continues," said LRO project scientist Richard Vondrak of Nasa's Goddard Space Flight Center in Greenbelt, US.

"They demonstrate how LRO will be used to identify the best destinations for the next journeys to the Moon."

Although the pictures provide a reminder⁸ of past lunar exploration, LRO's primary focus is on paving the way for the future.

Data returned by the mission will help Nasa identify safe landing sites for future explorers, locate potential resources, describe the Moon's radiation environment and demonstrate new technologies.